This study will investigate the safety, tolerability, PK and PD profile of AUT00206 after repeated doses in patients with stable but symptomatic schizophrenia, taking one or two established anti-psychotic drugs. The subjects will undergo brain imaging, tests of cognition and tests of auditory function and electrophysiological measures in addition to routine safety monitoring. Because of the pioneering and novel mechanism of action of this drug, a key objective is to characterize this range of biomarkers which will inform the future development of the drug.

Key inclusion Criteria:

• Male patients with a diagnosis of schizophrenia no more than 5 calendar years (before screening);
• Positive and negative symptoms assessed by PANSS;
• Medically and psychiatrically stable;
• On a stable dose of antipsychotic drugs;
• Able to give fully informed written consent and likely to comply with the requirements of the trial.

Key exclusion Criteria:

• clinically relevant, as assessed by a physician, abnormal findings at the screening assessment;
• sensitivity to excipients of the trial medication;
• current use of contraindicated drugs;
• participation in another clinical trial of unlicensed medicines within the previous 30 days;
• loss of more than 400 mL blood, within the previous 3 months; history of drug or alcohol dependence in the last year;
• significant acute or chronic illness;
• significant medical history or concurrent medical condition that warrants exclusion;
• objection by subject's physician

Male 18-50 Years